The invention relates generally to connectors of the type used in the handling and administration of parenteral fluids, and more particularly, to an adapter having both a valve mechanism for enabling a fluid interconnection to be made therewith without the use of a sharp cannula, and a sharpened cannula for interconnecting with other devices for fluid communication.
Injection sites for injecting fluid into or removing fluid from a system, such as a solution bag, a Y-site, blood tube, fluid bottle, or drug vial, are well known and widely used. Conventional injection sites generally involve a pierceable septum formed of an elastomeric material such as latex rubber or the like, captured in an access port. A sharp cannula is inserted into the access port piercing the septum to position the distal, open end of the cannula past the septum to make fluid connection with the interior of the access port. Upon withdrawal of the sharp cannula, the elastomeric septum reseals itself thus maintaining a sterile environment within the housing of the injection site. The outer surface of the septum of the injection site is wiped with an antiseptic before each use to prevent septic agents from being drawn into the access port by the piercing movement of the needle.
Due to the large number of devices available today that have pierceable septa, there is a continuing need to provide connectors that will access these devices. However, there is a large concern over the use of sharpened cannula devices. This is due, at least in part, to concern regarding the possibility of the transmission of blood-borne diseases through accidental needle punctures of persons handling the sharp cannulas. Connectors having no sharpened surfaces are desirable because such hazard is eliminated. Consequently, more recently, connectors for accommodating the injection and withdrawal of fluids without the use of sharp cannulas have been put to use in increasing numbers.
However, some existing needleless connectors suffer from various shortcomings. For example, relatively complex configurations employing a large number of parts are difficult to manufacture and assemble. This not only increases costs but may pose problems in service. Additionally, complex systems may not be intuitive to use which may prove distracting and therefore undesirable in the typical hospital room environment.
A further concern in the design of needleless connectors is the order of events in which the connection is made. For example, allowing fluid to escape or air to enter during interconnection due to the female connector being opened before the male connector is sufficiently seated is undesirable.
Additionally, some existing connectors accommodate a relatively large interior fluid volume requiring the injection of a commensurately large volume of fluid just to fill and prime the connector. If not taken into account, this fluid volume can detract from the volume of medicament injected into the patient and may be clinically significant. An inconvenient separate flushing procedure may be required in low dose injections or in the injection of unstable medicines due to this relatively large interior volume. Moreover, relatively complex geometries and the use of springs and the like in the wetted portion of the connector interior may give rise to "dead spaces" where fluid tends to linger due to poor flushing. Dead spaces give rise to problems similar to those occasioned by large interior volumes, again resulting in the inconvenient requirement of flushing.
Where metal components, such as metallic springs, are used in connectors, the metal components can interfere with magnetic resonance imaging used in hospitals. A further difficulty with the use of coiled metallic springs is the care that must be taken during manufacture. Allowing coiled springs to come into contact with each other while awaiting assembly into the valves may result in the springs becoming entangled with each other necessitating further handling before they can be installed.
Furthermore, it is desirable that needleless connectors be configured so that they can be easily cleaned by an antiseptic wipe, or otherwise sterilized, prior to making a connection. All exterior surfaces that may be involved in the transmission of fluid should be readily available for cleaning prior to the connection being made. Some prior connectors have a small rift or fissure defined by a clearance between parts. Such a feature is difficult and inconvenient to clean in attempting to sterilize a connector. Alternatively, connectors requiring cap to maintain a sterile connection port prior to use are undesirable because the extra steps involved in removing and replacing a cap are inconvenient, while the manufacture of the cap adds expense.
The ability to accommodate a high fluid flow rate is also desirable in a needleless connector. Physicians in certain situations order the administration of medicaments at highflow rates. Some prior connectors have restrictive geometries that limit their flow capacity such that administering fluids at high rates is impossible. The use of tortuous flow paths through a connector or multiple openings through a movable valve device through which the fluid must flow can result in a reduction of the maximum rated flow rate for the connector. With some restrictive geometries, higher flow rate requirements may not be possible under gravity head flow conditions and a positive pressure pump may be needed. Such connectors would be undesirable where pumps are not available and the usefulness of such connectors would be severely limited. The increase of flow rate capability and elimination of the tortuous fluid path can also facilitate priming of the connector and reduce potential blood hemolysis.
In addition, the performance of connectors incorporated into IV administration sets and used to allow automatic piggyback administration of medicaments becomes degraded when high flow rates through the connector cannot be accommodated. If high flow rates through the connector cannot be accommodated, automatic piggyback rates using infusion pumps must be limited to relatively low infusion rates. Otherwise, accidental simultaneous flow of primary fluids may occur when normal head height differentials are used between the primary and piggyback containers. Higher flow rates through the needleless connector allows higher flow rates of automatic piggyback administration without the possibility of accidental simultaneous flow of primary fluids.
A further consideration in the design of a connector is its compatibility with other connectors. In those cases where a cannula is mounted internally in a needleless connector to slide inside the fluid port of a male connector inserted into the needleless connector to establish the flow path, the outer diameter of that cannula must be closely controlled so that it can successfully mate with a wide range of male connectors. Making it too large may result in interference with certain male connectors thus rendering them unusable with the needleless connector. However, making the outer diameter of the cannula too small results in reduced fluid flow rates through the cannula.
Additionally, the internal cannula in the connector can damage the valve itself. In particular, the cannula can pierce, cut, or tear a rubber piston or septum mounted over it and damage the resealability of the valve. The cannula could also create particulate by tearing off portions of the rubber piston or septum when a male Luer is inserted into the connector. This may occur where the bore of the male Luer interferes with or is closely sized with the cannula and creates a punching action that removes a piece of the rubber septum. Consequently, it is desirable to avoid such configurations.
To accommodate both the need for continued use of pierceable septa devices and the use of blunt or needleless connectors for increased safety, there is a need for a connector that can mate with both devices. Such a connector would "adapt" the pierceable device to a needleless or blunt cannula access system. Once in place through the pierceable septum, it is desirable for the adapter to be anchored in position so that inadvertent disengagement does not occur, such as is possible when such a connector is engaged with a fluid bag suspended upside down.
A further consideration is expense. Because connectors are used in a medical environment, cleanliness is of large concern. Contamination among different fluid devices, patients, etc. must be avoided. Typically, most connectors are disposable so that after one use, they are then discarded to avoid such contamination. Of course, expense is a major concern for disposable items. Connectors should be made of fewer parts so that the parts and manufacturing expense is kept as low as possible to lessen the expense to the patient.
A further consideration is the expense to the hospital or other care-giving facility caused by having to stock numerous types of connectors. A single connector/adapter that fits all other devices would be preferable. Typically, a hospital must stock a variety of connectors to be assured of mating with various medical fluid devices. For example, a blood tube has a different opening than a solution bag and two different connectors must be stocked.
In some cases, a connector having a sharpened spike at one end and a female Luer lock fitting at the other end must be stocked. In order to adapt this connector to a needleless connection, a needleless valve must be connected with the Luer fitting, thus requiring the hospital to stock two components. In many cases, the sharpened spike is housed within a shroud to protect the handler from inadvertently puncturing himself or herself. The shroud is unlikely to fit all components to which a connector is needed, thus requiring the hospital to stock multiple types of sharpened spike connectors. The requirement to stock various components increases expense for the hospital. It would be desirable to stock a single connector that would mate with all medical fluid devices.
Hence, those concerned with the development of medical connectors have recognized the need for an adapter usable with both a pierceable injection site and a needleless connection system. In addition, there is a need for such a connector to have a small number of parts so that expense is reduced. Further, there is a need for an adapter that can mate with a wide variety of medical fluid devices so that only a single adapter is needed, thus obviating the need to stock multiple connector components. There is also a recognized need for an improved needleless connector that has a relatively simple construction with a small number of parts, that avoids the entry of air when the initial connection is made, that has reduced flushing requirements, that can be easily cleaned prior to use, and that permits a relatively high fluid flow rate. The present invention fulfills such needs and others.